1. Field of the Invention
This invention relates to packaging enclosure members and door opening systems and methods of operating such door opening systems for such enclosure members. More particularly this invention relates to enclosure members for the packaging of items and packaging structures for isolating contamination sensitive items such as electronic components.
2. Description of related art
For many years, packaging has been an integral part of the transportation and delivery of products to users. One principal function of packaging for these purposes has been to provide ease of handling and space efficient storage of the product, prior to use.
A further and often more important function of such packaging is the protection of the product from the time of production or manufacture until the time of use. Such protection has become particularly critical for electronic circuit components which are often subject to damage from a wide range of environmental conditions. Such conditions include, but are not limited to, accelerations during handling, such as impacts against surfaces, vibration, static electricity and contamination by vapors and particles and tampering.
Standardized mechanical interface (SMIF) systems have been designed for reducing particle contamination, including hermetically sealable, transportable containers.
U.S. Pat. No. 4,724,874 of M. Parikh for "Sealable Transportable Container Having a Particle Filtering System" provides a transportable container with a box with an interior space for containing articles, The box has a conduit for communicating between the interior space and the environment outside the box. The conduit contains a filter for filtering fluids passing through the conduit for alternate evacuation or pressurization. In discussing the prior art, U.S. Pat. No. 4,723,874, Cols.1 and 2, states as follows:
"A standardized mechanical interface (SMIF) has been proposed by the Hewlett-Packard Company as disclosed in U.S. Pat. Nos. 4,532,970, and 4,534,389. The purpose of the SMIF system is to reduce particle fluxes onto wafers. This end is accomplished by mechanically ensuring that during transportation, storage and processing of the wafers, the gaseous media (such as air or nitrogen) surrounding the wafers is essentially stationary relative to the wafers and by ensuring that particles from the ambient environment do not enter the immediate wafer environment. The SMIF system above consists of two parts:
"(1) a controlled environment including a clean process equipment canopy surrounding the wafer-handling mechanism of each processing machine, and PA1 "(2) a small, clean box having a quiet internal environment for carrying wafers from processing machine to processing machine.
"Systems of the above type are concerned with particle sizes which range from below 0.1 micrometers to above 200 micrometers. Particles with these sizes can be very damaging in semiconductor processing because of the small geometries employed in fabricating semiconductor devices. Typical semiconductor processes today employ geometries which are 1 micrometer and under. Unwanted contamination particles which have geometries measuring greater than 0.1 micrometer substantially interfere with 1 micrometer geometry semiconductor devices. The trend, of course, is to have smaller and smaller semiconductor processing geometries which today in research and development labs approach 0.1 micrometer and below. In the future, geometries will become smaller and smaller and hence smaller and smaller contamination particles become of interest.
"In typical processing environments today, `clean rooms` are established in which through filtering and other techniques, attempts are made to remove particles having geometries greater than 0.03 micrometers and above. There is a need, however, to improve the processing environment. In a clean room, wafers and other semiconductor processing articles are exposed to the full clean room environment. Since different people, different types of equipment and materials are also present in the clean room environment, the clean room cannot be maintained as particle free as desired. It is virtually impossible to maintain clean rooms free of particles of a 0.1 micrometer size and below.
"For this reason, systems such as the SMIF system have come under consideration. The proposed SMIF system, however, has some deficiencies. When SMIF boxes become contaminated, it is very difficult to remove small contaminant particles since the force of attraction of small particles to surfaces of the equipment is very high. When small particles become attached to a surface such as a SMIF box, they are not effectively removed by filtration techniques. Circulating and filtering air or other gas within a box does not readily remove the contamination particles which are attracted and hold in contact with surfaces. However, whenever an object such as a SMIF box is disturbed, by bumping for example, many small particles are freed from the surface and find their way as contaminants onto any semiconductor or other article which is present in the box. While scrubbing and washing techniques have been developed for removing small particles from equipment and surfaces, these processes tend to be cumbersome and furthermore are not entirely effective."
The Parikh patent states further, "Previous SMIF concepts have included the principle that the wafers move from the transportable container to the processing equipment through various apparatus by disturbing the least amount of air within the processing equipment. Thus the still air concept has pervaded prior SMIF transportable containers. The advantage of this is that any particulates in the air would not damage semiconductor wafers because the air remained relatively still during the transferring process. While this principle is still valid, it has been found that stagnant air too, has many particles which may also cause damage simply by static attraction. The recognition that stagnant air causes contamination and damage has created a need for active localized filtering of the SMIF box and the environments with which the semiconductor articles are exposed. This recognition is a departure from the previous SMIF concept which employed no active filtering means. The need for active filtering at localized areas and under specific conditions and at desired times has been left to this invention."
The same U.S. Pat. No. 4,724,874 of M. Parikh for "Sealable Transportable Container Having a Particle Filtering System" provides a transportable container with a box with an interior space for containing articles. The box has a conduit for communicating between the interior space and the environment outside the box. The conduit contains a filter for filtering fluids passing through the conduit for alternate evacuation or pressurization. The Parikh et al patent states, at the end of Col. 2 thereof, "In accordance with the above background, there is a need for an improved system which can be standardized and which is effective for reducing contamination using an active filtering system."
It is important for packaging to protect against contamination or tampering (e.g. removal and replacement of the device in a protective, shock absorbing packaging foam under conditions where damage could occur).
The maintenance of an adequately clean manufacturing environment has led to increased manipulation of the packaging and items contained therein by automated processing equipment. Therefore, isolation structures must be adapted to be manipulated by such equipment in addition to providing the required types of protection for the packaged items. This adaptation often requires both the packaging and the automated equipment to be specially modified and standardized, increasing costs and reducing the generality of application of the automated equipment.
It is accordingly important that such equipment can be opened and closed with maximum efficiency while maintaining the clean environment about the materials housed within the enclosure member during the process of opening and closing.